JP7110834B2 - EPOXY RESIN COMPOSITION FOR SHEET MOLDING COMPOUND, SHEET MOLDING COMPOUND, AND MOLDED PRODUCT - Google Patents

Description

TECHNICAL FIELD The present invention relates to epoxy resin compositions for sheet molding compounds, sheet molding compounds, and molded articles.

So-called FRP, in which a thermosetting resin is reinforced with a fiber reinforcing material, is used in many fields such as industrial parts, housing parts, and automobile parts. Furthermore, fiber-reinforced resin composite materials, in which thermosetting resins such as epoxy resins and unsaturated polyester resins are reinforced with carbon fiber as a fiber reinforcement, are attracting attention for their excellent heat resistance and mechanical strength while being lightweight. Its use in structural applications is expanding. In addition, since discontinuous fibers are used as fiber reinforcement, the applicable range of molding shapes is wider than that of continuous fibers, remnants can be reused, and different material parts can be inserted. Due to its wide range, a sheet molding compound (hereinafter sometimes abbreviated as "SMC") is widely used. SMCs composed of unsaturated polyester resins and vinyl ester resins, which are generally known as thermosetting resins for SMCs, have problems such as emissions of volatile organic compounds. For this reason, studies on SMC using epoxy resin are underway.

Known SMCs containing epoxy resins as main components include epoxy resin compositions and molding materials containing aromatic epoxy resins, alicyclic diamines, curing agents for epoxy resins, and aliphatic epoxy resins as essential components (for example, , see Patent Document 1). Although this molding material has excellent storage stability, it has a low melt viscosity, and there are problems in that the resin excessively flows out from the fiber reinforcing material, and in that it takes several days to thicken the epoxy resin composition, which is a productivity problem. .

JP 2018-66026 A

The problem to be solved by the present invention is to provide an epoxy resin composition for a sheet molding compound, a sheet molding compound, and a molded article thereof, which are excellent in moldability such as resin flowability, thickening property, and productivity such as film peelability. to do.

The present inventors have found that a sheet molding compound having excellent moldability and productivity can be obtained from an epoxy resin composition for a sheet molding compound containing a specific epoxy resin, polyisocyanate, and an epoxy resin curing agent. , completed the present invention.

That is, a sheet molding compound characterized by containing an epoxy resin (A) having an α-glycol group in the range of 0.1 to 1 meq/g, a polyisocyanate (B), and an epoxy resin curing agent (C). The present invention relates to an epoxy resin composition for , a sheet molding compound using the same, and a molded product.

The sheet molding compound and molded product obtained from the present invention are excellent in productivity, moldability, etc. It can be suitably used for building and civil engineering members, exteriors and structures of OA equipment, and the like.

The epoxy resin composition for a sheet molding compound of the present invention comprises an epoxy resin (A) having an α-glycol group in the range of 0.1 to 1 meq/g, a polyisocyanate (B), and an epoxy resin curing agent (C). contains

The epoxy resin (A) has an α-glycol group in the range of 0.1 to 1 meq/g. It is preferably 2 meq/g or more, and preferably 0.9 meq/g or less because the influence of water absorption can be further reduced.

The epoxy resin (A) preferably has a number average molecular weight of 50 to 1,000, more preferably 100 to 500. When the number molecular weight is 1,000 or more, the viscosity becomes high and the impregnation into the reinforcing fiber material is poor.

The epoxy equivalent of the epoxy resin (A) is preferably in the range of 150 to 1500 g/eq, more preferably in the range of 170 to 500 g/eq, since strength and handleability are further improved.

The viscosity of the epoxy resin (A) is preferably in the range of 500 to 100,000 mPa s, more preferably in the range of 1,000 to 80,000 mPa s, because the handling property and the impregnation property into the fiber reinforcing material are further improved. more preferred.

Examples of the epoxy resin (A) include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol fluorene type epoxy resins, bisphenol type epoxy resins such as biscresol fluorene type epoxy resins, phenol novolac type epoxy resins, and cresol novolak type epoxy resins. Glycidyl ether of phenol, trimethylolpropane triglycidyl ether, diglycidyl ether of alkylene oxide adduct of bisphenol A, hydrogenated bisphenol glycidyl ethers of polyhydric alcohols such as the diglycidyl ether of A, alicyclic epoxy resins, diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl-p-oxybenzoic acid, glycidyl esters such as dimer acid glycidyl ester, glycidylamines such as tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, N,N-diglycidylaniline; and heterocyclic epoxy resins such as triglycidyl isocyanurate. Among these, aromatic epoxy resins are preferable, and bifunctional aromatic epoxy resins are more preferable, bisphenol A type epoxy resin and bisphenol F type epoxy resin, because they are superior in molding strength and flowability of the molding material during molding. Resins are particularly preferred. These epoxy resins can be used alone or in combination of two or more.

The epoxy resin (A) may be produced by a so-called one-step method in which bisphenols and epihalohydrin are reacted, or bisphenol-type epoxy resins are produced by reacting bisphenols and epihalohydrin. After that, the epoxy resin may be produced by a so-called two-step method in which the bisphenol is further reacted with the epoxy resin.

As a one-step method, for example, (1) a mixture of epichlorohydrin and glycidol is reacted with bisphenols to reach the target molecular weight, (2) epichlorohydrin is reacted in advance with an alkali metal hydroxide, (3) reacting epichlorohydrin and bisphenols to a target molecular weight to obtain a bisphenol-type epoxy resin; and then reacting it with an alkali metal hydroxide to α-glycolize the terminal epoxy group.

As a two-step method, for example, (4) epichlorohydrin is preliminarily reacted with an alkali metal hydroxide to form a mixture of epichlorohydrin and glycidol, which is then reacted with bisphenols to obtain an intermediate liquid epoxy resin. (5) reacting epichlorohydrin with bisphenols to obtain an intermediate liquid epoxy resin, which is further reacted with glycidol and bisphenols to increase the molecular weight; (6) ) A method of reacting epichlorohydrin with bisphenols to obtain an intermediate liquid epoxy resin, reacting this with an alkali metal hydroxide to α-glycolize the terminal epoxy groups, and then increasing the molecular weight with bisphenols; (7) epichlorohydrin; is reacted with bisphenols to obtain an intermediate liquid epoxy resin, which is further polymerized with bisphenols to obtain a bisphenol-type epoxy resin, and then reacted with an alkali metal hydroxide to convert the terminal epoxy group to α-glycol. and the like.

Among these, the latter two-step method is preferable, and the method (4) is particularly preferable, because it is easy to adjust the amount of α-glycol to the target.

The method (4) is further detailed below. That is, in method (4), epichlorohydrin and an aqueous alkali metal hydroxide solution are reacted to obtain a mixture of epichlorohydrin and glycidol (step 1), and the mixture and bisphenols are reacted in the presence of an alkali metal hydroxide. An intermediate liquid epoxy resin is obtained by reacting (step 2), and then the intermediate liquid epoxy resin is reacted with bisphenols to increase the molecular weight (step 3).

The reaction conditions of epichlorohydrin and an aqueous alkali metal hydroxide solution in step 1 are not particularly limited, but epichlorohydrin and an aqueous solution of 1 to 20% by weight of an alkali metal hydroxide are heated at 70 to 100° C., preferably A method of contacting them at 85 to 95° C. can be mentioned, and a mixture of glycidol and epichlorohydrin can be easily produced by such a reaction. The abundance ratio of glycidol and epichlorohydrin in the mixture is not particularly limited. It is preferable from the point that adjustment of content is easy.

Next, in step 2, the obtained mixture of epichlorohydrin and glycidol and bisphenols are reacted in the presence of an alkali metal hydroxide. Here, the specific method is not particularly limited, but from the viewpoint of productivity, after the reaction in step 1 is completed, the bisphenols are added to the reaction vessel and dissolved, and then the alkali metal hydroxide is added. method.

The reaction ratio of the mixture of epichlorohydrin and glycidol and the bisphenols is not particularly limited, but the molar ratio of the former/latter = 5 to 20 mol makes it easy to adjust the desired amount of α-glycol. .

The epoxy resin composition of the present invention may contain other epoxy resins than the epoxy resin (A).

As other epoxy resins, those having an α-glycol group of less than 0.1 meq/g among the epoxy resins listed as usable for the epoxy resin (A) can be used. Other epoxy resins can be used alone or in combination of two or more.

Moreover, when using the epoxy resin (A) and other epoxy resins, it is preferable to use an epoxy diluent in combination, since it facilitates adjustment of the viscosity and adjustment of the epoxy equivalent.

Examples of the epoxy diluent include phenyl glycidyl ether, alcohol glycidyl ether, alkyl glycidyl ether, alkyl glycidyl ester, α-olefin epoxide, alkylphenyl glycidyl ether, alkylphenol glycidyl ether and the like. Here, the alkyl group is preferably a linear or branched alkyl group having 1 to 20 carbon atoms. Furthermore, it is preferably liquid.

Among these, it is preferable to use phenyl glycidyl ether, alkyl glycidyl ether, alkylphenyl glycidyl ether, butanediol diglycidyl ether from the viewpoint of lower viscosity and easier adjustment of the viscosity of the composition. From the viewpoint of adhesiveness and flexibility, it is preferable to use alkylphenyl glycidyl ether and butanediol diglycidyl ether.

As the epoxy diluent, various phenols and alcohols are reacted with epihalohydrin to form glycidyl ether, and various commercially available ones can be used.

Examples of the commercially available products include YED series manufactured by Mitsubishi Chemical Corporation, special epoxy products marketed as monoepoxy type manufactured by Sakamoto Pharmaceutical Co., Ltd., Epiol series manufactured by NOF Corporation, and ADEKA Corporation. ADEKA GLYCIROL ED series, and "EPICLON 520" manufactured by DIC Corporation.

The viscosity of the epoxy diluent is preferably in the range of 1 to 1,000 mPa·s, more preferably in the range of 1 to 500 mPa·s, since the fiber impregnating property of the epoxy resin composition is further improved.

The amount of the epoxy diluent used is 5 to 2,000 parts by mass based on the total 100 parts by mass of the epoxy resin (A) and other epoxy resins, because the adhesiveness with the fiber reinforcing material is better. A range is preferred.

The polyisocyanate (B) is, for example, diphenylmethane diisocyanate (4,4′-isomer, 2,4′-isomer, or 2,2′-isomer, or a mixture thereof), carbodiimide-modified diphenylmethane diisocyanate, or nurate-modified diphenylmethane diisocyanate. Diphenylmethane diisocyanate modified products such as polyol modified polyol modified with a polyol having a number average molecular weight of 1,000 or less such as diethylene glycol or dipropylene glycol, tolylene diisocyanate, tolidine diisocyanate, polymethylene poly Aromatic polyisocyanates such as phenyl polyisocyanate, xylylene diisocyanate, 1,5-naphthalene diisocyanate and tetramethylxylene diisocyanate; Alicyclic polyisocyanates such as isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate and norbornene diisocyanate; Aliphatic polyisocyanates such as hexamethylene diisocyanate, nurate-modified hexamethylene diisocyanate, burette-modified, adduct, and dimer acid diisocyanate can be used. Among these, aromatic polyisocyanates are preferable, and carbodiimide-modified diphenylmethane diisocyanate is more preferable, since a molding material having excellent handleability (film peelability and tackiness) can be obtained. The carbodiimide-modified diphenylmethane diisocyanate includes, in addition to those having a carbodiimide group, those having a urethane imine structure obtained by further adding an isocyanate group to the carbodiimide group. Moreover, these polyisocyanates (B) can be used alone or in combination of two or more. Furthermore, it can be used together with a polyol to react with the hydroxyl groups of the polyol.

The polyisocyanate (B) is preferably liquid at room temperature because it improves the dispersibility and the appearance of the molded product. 500 mPa·s is more preferable, and 1 to 1,000 mPa·s is particularly preferable. In addition, when the viscosity is as low as 500 mPa·s, it has the effect of adjusting the viscosity, and can have the effect of both a thickener and a diluent.

The molar ratio (NCO/αOH) between the isocyanate group (NCO) of the polyisocyanate (B) and the α-glycol group (αOH) of the epoxy resin (A) is 0.00, because the strength of the molded article is further improved. It is preferably in the range of 1-30, more preferably 1-15.

Examples of the epoxy resin curing agent (C) include amine compounds, amide compounds, acid anhydride compounds, and phenol compounds. Examples of amine compounds include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole, BF3-amine complexes, guanidine derivatives, etc. Examples of amide compounds include dicyandiamide and linolenic acid. Examples of acid anhydride compounds include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, and methyltetrahydrophthalic anhydride. acid, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, etc., and phenolic compounds include phenol novolak resin, cresol novolac resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin, dicyclopentadiene. Polyhydric phenol novolac resin synthesized from polyhydric hydroxy compound and formaldehyde represented by phenol addition type resin, phenol aralkyl resin (Zyloc resin), resorcinol novolak resin, naphthol aralkyl resin, trimethylolmethane resin, tetraphenylolethane resin , naphthol novolac resin, naphthol-phenol co-condensed novolak resin, naphthol-cresol co-condensed novolac resin, biphenyl-modified phenol resin (polyhydric phenol compound with phenol nucleus linked by bismethylene group), biphenyl-modified naphthol resin (phenol core-linked polyvalent naphthol compounds), aminotriazine-modified phenol resins (polyhydric phenol compounds with phenol nuclei linked by melamine, benzoguanamine, etc.) and alkoxy group-containing aromatic ring-modified novolac resins (formaldehyde and polyhydric phenol compounds such as polyhydric phenol compounds having aromatic rings linked thereto). These epoxy resin curing agents (C) can be used alone or in combination of two or more.

Among these, amide compounds and amine compounds are preferable, and dicyandiamide and imidazole are more preferable because of their high curability and excellent rapid curability.

The epoxy resin curing agent (C) is preferably used in an amount of 1 to 40 parts by mass with respect to 100 parts by mass of the epoxy resin.

A curing accelerator (c1) can also be used as a part of the epoxy resin curing agent (C), and a urea compound is preferable from the viewpoint of improving the mechanical properties of the molded product, and the thermal properties of the fiber-reinforced composite material ( Imidazole compounds are preferred from the viewpoint of increasing heat resistance).

Urea compounds include 3-phenyl-1,1-dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, 3-(3-chloro-4-methylphenyl)-1,1- dimethylurea, 2,4-bis(3,3-dimethylureido)toluene, 1,1'-(4-methyl-1,3-phenylene)bis(3,3-dimethylurea) and the like.

Examples of imidazole compounds include imidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4 -methylimidazole, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1') ]-ethyl-s-triazineisocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole and the like.

Several curing accelerators (c1) of the present invention can be used in combination within the range of 1 to 40 parts by mass per 100 parts by mass of the epoxy resin.

The epoxy resin composition of the present invention may contain components other than the epoxy resin (A), the polyisocyanate (B), and the curing agent for epoxy resin (C). It is preferable to contain the thermoplastic resin particles (D), since it further improves the

The thermoplastic resin particles (D) are resin powders containing at least one monomer unit selected from acrylic acid esters, methacrylic acid esters, dienes, and monomers copolymerizable therewith. , a thermoplastic resin powder composed of a core layer and a shell layer is used as an active ingredient. Acrylic acid esters and methacrylic acid esters used for this component include, for example, ethyl (meth) acrylate, n-butyl (meth) acrylate, methyl methacrylate, butyl (meth) acrylate, n-propyl (meth) acrylate, and 2-ethylhexyl. (Meth)acrylate, n-decyl methacrylate, isobutyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and the like.

Examples of diene-based monomers include conjugated diene-based compounds such as butadiene, isoprene, 1,3-pentadiene, cyclopentadiene and dicyclopentadiene, and non-conjugated diene-based compounds such as 1,4-hexadiene and ethylidenenorbornene. mentioned.

Examples of monomers copolymerizable with these include aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, pt-butylstyrene and chlorostyrene, acrylamide, N-methylolacrylamide and N-butoxymethylacrylamide. methacrylamide compounds such as methacrylamide, N-methylol methacrylamide, N-butoxymethyl methacrylamide, glycidyl acrylate, glycidyl methacrylate and allyl glycidyl acrylate. Preferred are the aromatic vinyl compounds described above.

The content of the thermoplastic resin particles (D) is preferably in the range of 1 part by mass or more and less than 10 parts by mass with respect to 100 parts by mass of the epoxy resin, in order to improve the thickening property.

The viscosity of the epoxy resin composition of the present invention is preferably in the range of 100 to 6,000 mPa s, and more preferably in the range of 300 to 3,500 mPa s, because the handleability and impregnation into the fiber reinforcing material are further improved. preferable.

The SMC of the present invention contains the above-described epoxy resin composition for SMC and the fiber reinforcing material (E) as essential components, is excellent in productivity, has diversity in design and joining of different materials, and can be molded. Excellent in nature.

Fibers cut to a length of 2.5 to 50 mm are used as the fiber reinforcing material (E). Fibers cut to 5-40 mm are more preferred.

Examples of the fiber reinforcing material (E) include glass fiber, carbon fiber, silicon carbide fiber, pulp, hemp, cotton, nylon, polyester, acrylic, polyurethane, polyimide, or polyamide fiber made of aramid such as Kevlar and Nomex. etc. Among these, carbon fiber is preferable because a molded product with high strength can be obtained.

As the carbon fiber, various types such as polyacrylonitrile, pitch, and rayon can be used. Among these, polyacrylonitrile is preferable because high-strength carbon fiber can be easily obtained.

Further, the number of filaments in the fiber bundle used as the carbon fiber is preferably 1,000 to 60,000 because the resin impregnation property and the mechanical properties of the molded product are further improved.

The content of the fiber reinforcing material (E) in the components of the SMC of the present invention is preferably in the range of 25 to 80% by mass, and 40 to 70% by mass, because the mechanical properties of the resulting molded product are further improved. % range is more preferred, with 45 to 65 mass % being particularly preferred. If the fiber content is too low, it may not be possible to obtain a high-strength molded product. A strong molded product may not be obtained.

Further, the carbon fibers in the SMC of the present invention are impregnated with the resin in a random fiber direction.

Components other than the epoxy resin composition for SMC and the fiber reinforcing material (E) described above may be used as components of the SMC of the present invention. Thermoplastic resin other than particles (D), polymerization inhibitor, curing accelerator, filler, low shrinkage agent, release agent, thickener, viscosity reducer, pigment, antioxidant, plasticizer, flame retardant, antibacterial agents, ultraviolet stabilizers, storage stabilizers, reinforcing agents, photocuring agents, and the like.

Examples of the thermosetting resin include vinyl ester resin, vinyl urethane resin, unsaturated polyester resin, acrylic resin, phenol resin, melamine resin, and furan resin. Moreover, these thermosetting resins can be used alone or in combination of two or more.

Examples of the thermoplastic resin include polyamide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polycarbonate resin, urethane resin, polypropylene resin, polyethylene resin, polystyrene resin, acrylic resin, polybutadiene resin, polyisoprene resin, and copolymers thereof. and the like. Moreover, these thermoplastic resins can be used alone or in combination of two or more.

Examples of the filler include inorganic compounds and organic compounds, which can be used to adjust physical properties such as strength, elastic modulus, impact strength, and fatigue durability of molded articles.

Examples of the inorganic compound include calcium carbonate, magnesium carbonate, barium sulfate, mica, talc, kaolin, clay, celite, asbestos, barite, baryta, silica, silica sand, dolomite limestone, gypsum, aluminum fine powder, hollow balloons, Alumina, glass powder, aluminum hydroxide, cold water stone, zirconium oxide, antimony trioxide, titanium oxide, molybdenum dioxide, iron powder and the like.

Examples of the organic compound include powders of natural polysaccharides such as cellulose and chitin, powders of synthetic resins, and the like, and powders of synthetic resins include hard resins, soft rubbers, elastomers, polymers (copolymers), and the like. Particles having a multi-layered structure such as organic powders and core-shell type particles can be used. Specific examples include particles of butadiene rubber and/or acrylic rubber, urethane rubber, silicon rubber, polyimide resin powder, fluororesin powder, phenol resin powder, and the like. These fillers can be used alone or in combination of two or more.

Examples of the release agent include zinc stearate, calcium stearate, paraffin wax, polyethylene wax, carnauba wax, and fluorine compounds. Fluorine compounds and paraffin waxes are preferred. These release agents can be used alone or in combination of two or more.

Examples of the thickener include metal oxides and metal hydroxides such as magnesium oxide, magnesium hydroxide, calcium oxide and calcium hydroxide, acrylic resin fine particles, and the like, and the fiber-reinforced molding material of the present invention. It can be selected as appropriate depending on the handling property. These thickeners can be used alone or in combination of two or more.

As a method for producing the SMC of the present invention, the epoxy resin (A), the polyisocyanate (B), and the Each component such as a curing agent (C) and thermoplastic resin particles (D) is mixed and dispersed, and the resulting resin composition is applied to carrier films placed above and below so as to have a uniform thickness. The reinforcing material (E) is sandwiched between the resin composition on the carrier films provided above and below, and then the whole is passed between impregnation rolls and pressure is applied to impregnate the fiber reinforcing material (E) with the resin composition. A method of winding the film into a roll or folding the film into a zigzag pattern, and the like, can be exemplified. Further, it is preferable to thicken the mixture by aging at room temperature or at a temperature of 20 to 60° C. after this. As the carrier film, a polyethylene film, a polypropylene film, a laminate film of polyethylene and polypropylene, polyethylene terephthalate, nylon, or the like can be used.

The molded article of the present invention can be obtained from the SMC, and hot compression molding is preferable as the molding method from the viewpoint of excellent productivity and excellent design diversity.

For the heat compression molding, for example, a predetermined amount of the SMC is weighed, put into a mold preheated to 110 to 180° C., the mold is clamped by a compression molding machine, and the molding material is shaped. A manufacturing method is used in which the molding material is cured by maintaining a molding pressure of 1 to 30 MPa, and then the molded article is removed to obtain the molded article. As a specific molding condition, a mold temperature of 120 to 160 ° C. in the mold and a molding pressure of 1 to 10 MPa for 1 to 2 minutes per 1 mm of the thickness of the molded product are preferable. is more improved, the molding conditions are more preferably a mold temperature of 140 to 160° C. and a molding pressure of 1 to 10 MPa for 30 to 90 seconds per 1 mm of the thickness of the molded product.

The SMC of the present invention is excellent in productivity, moldability, etc., and the resulting molded articles include automobile members, railway vehicle members, aerospace aircraft members, ship members, housing equipment members, sports members, light vehicle members, and construction and civil engineering members. , OA equipment and the like.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples. The epoxy equivalent is measured according to the method of JIS K 7236: 2009, and the viscosity of the epoxy resin is measured using an E-type viscometer (TV-22 manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. is measured. Moreover, the average molecular weight is measured under the following GPC measurement conditions.

[GPC measurement conditions]
Measuring device: "HLC-8220 GPC" manufactured by Tosoh Corporation,
Column: Guard column "HXL-L" manufactured by Tosoh Corporation
+ "TSK-GEL G2000HXL" manufactured by Tosoh Corporation
+ "TSK-GEL G2000HXL" manufactured by Tosoh Corporation
+ "TSK-GEL G3000HXL" manufactured by Tosoh Corporation
+ "TSK-GEL G4000HXL" manufactured by Tosoh Corporation
Detector: RI (differential refractometer)
Data processing: "GPC-8020 model II version 4.10" manufactured by Tosoh Corporation
Measurement conditions: Column temperature 40°C
Developing solvent Tetrahydrofuran
Flow rate 1.0 ml/min Standard sample: The following monodisperse polystyrene with known molecular weight was used according to the measurement manual of "GPC-8020 model II version 4.10".

(Polystyrene used)
"A-500" manufactured by Tosoh Corporation
"A-1000" manufactured by Tosoh Corporation
"A-2500" manufactured by Tosoh Corporation
"A-5000" manufactured by Tosoh Corporation
"F-1" manufactured by Tosoh Corporation
"F-2" manufactured by Tosoh Corporation
"F-4" manufactured by Tosoh Corporation
"F-10" manufactured by Tosoh Corporation
"F-20" manufactured by Tosoh Corporation
"F-40" manufactured by Tosoh Corporation
"F-80" manufactured by Tosoh Corporation
"F-128" manufactured by Tosoh Corporation
Sample: A 1.0% by mass tetrahydrofuran solution in terms of resin solid content filtered through a microfilter (50 μl).

(Synthesis Example 1: Synthesis of epoxy resin (A-1))
925 parts by mass (10.0 mol) of epichlorohydrin and 92 parts by mass of a 5% sodium hydroxide aqueous solution were charged in a flask equipped with a nitrogen inlet tube, a condenser tube, a thermometer, and a stirrer, and the temperature was raised to 80°C. , and stirred for 8 hours. Then, after lowering the temperature to 60° C., 114 parts by mass (1.0 mol) of bisphenol A, 139 parts by mass of n-butanol, and 2 parts by mass of tetraethylbenzylammonium chloride were charged and dissolved. After 90 parts by mass (1.1 mol) of a 49% sodium hydroxide aqueous solution was added dropwise over 5 hours, unreacted epichlorohydrin was distilled off by distillation under reduced pressure, and 59 parts by mass of methyl ethyl ketone and 177 parts by mass of n-butanol was added and dissolved. Then, 10 parts by mass of a 10% aqueous sodium hydroxide solution was added, the temperature was raised to 80° C., and the reaction was allowed to proceed for 2 hours. The obtained reactant was washed with 150 parts by mass of water. This was repeated 3 times, and it was confirmed that the pH of the washing liquid had become neutral. Azeotropic dehydration was performed, and after microfiltration, the solvent was distilled off under reduced pressure to obtain 210 parts by mass of epoxy resin (A-1). The epoxy resin (A-1) had an α-glycol group of 0.3 meq/g, an epoxy equivalent of 199 g/eq, a viscosity of 17,400 mPa·s and a number average molecular weight of 208.

(Example 1)
90 parts by mass of epoxy resin (A-1), epoxy diluent ("XY-622" manufactured by ANHUI XINYUAN Chemical Co., 1,4-butanediol diglycidyl ether, epoxy equivalent: 131 g / eq, α-glycol: 0.04 meq/g, viscosity: 17 mPa s, number average molecular weight: 143) 10 parts by mass, internal release agent ("FB-962" manufactured by Daikin Industries, Ltd.) 0.8 parts by mass, curing agent for epoxy resin (Mitsubishi Chemical Corporation Company "DICY7", dicyandiamide) 8 parts by mass, curing accelerator (DIC Corporation "B-605-IM", alkyl urea type) 5 parts by mass were mixed with a triple roll, thermoplastic resin particles (Aica "F303" manufactured by Kogyo Co., Ltd., core-shell type poly(meth)acrylic acid ester-based organic fine particles) 1.4 parts by mass, polyisocyanate (manufactured by Mitsui Chemicals, Inc. "Cosmonate LL", carbodiimide-modified MDI, viscosity: 35 mPa s ) was mixed with 28.8 parts by mass to obtain an epoxy resin composition for SMC (X-1).

[Measurement of α-glycol group amount]
Dissolve 3 g of sample in 25 ml of chloroform, add 25 ml of benzyltrimethylperiodate ammonium solution, react for 2.5 hours, add 5 ml of 2N aqueous sulfuric acid solution and 15 ml of 20% potassium iodide aqueous solution, add 0.1N sodium thiosulfate solution. The solution was titrated.

[Evaluation of resin flowability]
In accordance with JIS K-7071, 10 g of the epoxy resin composition (X-1) for SMC was pressed at a temperature of 150° C., a load of 5 N, and a pressurization time of 30 seconds. The total length in two vertical directions was evaluated so as to obtain the length.
○: 50 mm or more and less than 100 mm, the melt viscosity is appropriate ×: 100 mm or more, the melt viscosity is low, and the resin flows too much

[Initial viscosity]
Each epoxy resin composition (X-1) for SMC immediately after preparation was measured at 25° C. with VISCOMETER RB-85H manufactured by Toki Sangyo Co., Ltd.

[Evaluation of thickening property]
The epoxy resin composition (X-1) after aging at 25° C. for 24 hours was measured at 25° C. with a VISCOMETER RB-85H manufactured by Toki Sangyo Co., Ltd. and evaluated according to the following criteria.
○: Viscosity was 10,000 mPa s or more ×: Viscosity was less than 10,000 mPa s

[Preparation of SMC]
The resin composition (X-1) obtained above was applied to a polyethylene-polypropylene laminate film in an average coating amount of 1 kg/m ² , and a carbon fiber roving (manufactured by Toray Industries, Inc. " T700SC-12000-50C”) cut to 12.5 mm (hereinafter abbreviated as fiber reinforcement (E-1)) has no fiber directionality and has a uniform thickness and a carbon fiber content of 47% by mass. It was uniformly dropped from the air so that the resin composition (X-1) was applied in the same manner, and the carbon fiber was impregnated with the resin by sandwiching it with a film coated with the resin composition (X-1). ). The basis weight of this SMC was 2 kg/m ² .

[Evaluation of film peelability]
The SMC (Y-1) obtained above was checked for releasability from the polypropylene film at 23° C., and expressed in the following 4-grade evaluation.
A: No stickiness and easy to peel off from the film.
◯: Slightly sticky, but can be easily peeled off from the film.
Δ: Sticky, and deposits remain when part of the film is peeled off.
x: Sticks to the film.

[Production of molded product]
The SMC (Y-1) obtained above is pressed against the projected area of a 30 cm square mold at a charge rate of 75% under the molding conditions of a mold temperature of 150° C., a pressing time of 7 minutes, and a pressing force of 10 MPa. It was molded to obtain a flat molded product (Z-1) having a thickness of 2 mm.

[Evaluation of heat resistance]
A test piece was cut out from each of the flat plate molded products (Z-1) obtained above, and this test piece was subjected to a heating rate of 10° C./min using “DSC Q-100” manufactured by TA Instruments. Temperature drop rate: quenching The glass transition temperature (Tg) was measured by 2nd-run measurement, and the heat resistance was evaluated according to the following criteria.
○: glass transition temperature is 100 ° C. or higher ×: glass transition temperature is less than 100 ° C.

(Examples 2-6)
SMC resin compositions (X-2) to (X-6), SMC (Y-2) to (Y-6), and molded articles ( Z-1) to (Z-6) were obtained and evaluated.

(Comparative Examples 1 to 3)
SMC resin compositions (RX-1) to (RX-3), SMC (RY-1) to (RY-3), and molded articles ( RZ-1) to (RZ-3) were obtained and evaluated.

"Epiclon 850-S" in Table 2: manufactured by DIC Corporation, bisphenol A type epoxy resin, epoxy equivalent: 189 g/eq, α-glycol: 0.02 meq/g, viscosity: 13,100 mPa s, number average molecular weight ;301)

It was confirmed that the epoxy resin compositions for SMC of the present invention of Examples 1 to 6 had good resin flowability and thickening property, and also had excellent film peelability when made into SMC.

On the other hand, Comparative Examples 1 and 2 are examples that do not contain the epoxy resin (A) having an α-glycol group in the range of 0.1 to 1 meq/g, which is an essential component of the present invention. It was confirmed that the viscosity was poor and the SMC film releasability was poor.

Further, Comparative Example 3, which does not contain polyisocyanate, which is an essential component of the present invention, was confirmed to have poor resin flowability and thickening properties, and poor SMC film peelability.

Claims (6)

Epoxy for sheet molding compound, comprising an epoxy resin (A) having an α-glycol group in the range of 0.1 to 1 meq/g, a polyisocyanate (B), and an epoxy resin curing agent (C). Resin composition. The molar ratio (NCO/αOH) between the isocyanate group (NCO) in the polyisocyanate (B) and the α-glycol group (αOH) in the epoxy resin (A) is in the range of 0.1 to 30. Item 2. The epoxy resin composition for sheet molding compound according to item 1. 3. The epoxy resin composition for sheet molding compound according to claim 1 or 2, wherein the polyisocyanate (B) is an aromatic polyisocyanate. 4. The epoxy resin composition for sheet molding compound according to any one of claims 1 to 3, further comprising thermoplastic resin particles (D). A sheet molding compound comprising the epoxy resin composition for a sheet molding compound according to any one of claims 1 to 4 and a fiber reinforcing material (E). A molded article of the sheet molding compound according to claim 5 .